1. Field of the Invention
The present invention relates to an image processing device, an image processing method and an image processing system for performing print simulations with ink of color different from the process colors.
2. Description of the Related Art
In DTP (Desktop Publishing), image creation, image processing, image editing and the like are performed on a processing device such as a personal computer or a workstation to create a page layout. Then, based on the page layout a film is created with which to expose a printing plate (CEPS; color electronic prepress system), or a printing plate is created by writing directly onto a plate (CTP; computer to plate).
Further, when proofing is performed before printing using of an actual printing plate, a WYSIWYG function or the like is used to print out a page layout, which is displayed on a monitor, by a print outputting device such as a page printer (i.e., Comprehensive layout output).
In general process color printing, four process colors of Cyan, Magenta, Yellow and Black (CMYK) are used, however, an ink of color other than the process colors (spot color) may be used if necessary. In addition, these days, two-color printing may be performed in order to reduce printing cost. In this case, one of the process colors and a spot color are used as the two colors for two-color printing or alternatively, two spot colors may be used to give special effects.
In performing a two-color print simulation with the use of spot colors, if only process colors can be used to provide the print output, it is difficult to check the actual final look of the printed material.
Therefore, there has been proposed a method for performing spot color print simulations wherein: printing using plates and inks of the actual spot colors to be used in a two-color printing is carried out; color charts for these colors are then generated by taking readings from the printouts; the spot color use profile is created (CMYK-L*a*b* look-up tables); the spot colors use profile is combined with a printer use profile (L*a*b*-C′M′Y′K′ look-up-tables) using a color management function; and by doing this the conversion from the process colors to the substituted spot colors (CMYK-C′M′Y′K′) can be created (see Japanese Patent Application Laid-Open (JP-A) No. 2000-062253, for example).
Further, JP-A No. 2003-348366 has proposed a method of outputting color comprehensive layout by replacing each color of a document, which has been created with any two colors of C, M, Y and K, with a desired ink color (spot color).
However, in performing a two-color print simulation with spot colors, only one spot color is instructed (selected) per color plate of the process colors. For this reason, if the instructed spot color has not exerted the expected effect, another spot color must be separately instructed for the color plate and a print simulation performed once again.
Furthermore, if several print simulations are performed on different dates and hours, there may occur density fluctuations in print outputs. In order to simulate how such density fluctuations will appear on a printed object, it is necessary to look for spot colors with the same hue but different densities. This makes it difficult to perform a print simulation in consideration of density variations of a spot color.